cflow binary package in Ubuntu Lunar amd64

 GNU cflow analyzes a collection of source files written in C language
 and outputs a graph charting dependencies between various functions.
 .
 GNU cflow is able to produce two kinds of graphs: direct and reverse.
 Direct graph begins with the main function (or any other function),
 and displays recursively all functions called by it. In contrast,
 reverse graph is a set of subgraphs, charting for each function its
 callers, in the reverse order. Due to their tree-like appearance,
 graphs can also be called trees.
 .
 In addition to these two output modes, cflow is able to produce a
 cross-reference listing of all the symbols encountered in the input
 files.
 .
 GNU cflow also provides detailed control over symbols that will appear
 in its output, allowing to omit those that are of no interest to the
 user. The exact appearance of the output graphs is also configurable.

Source package